134,713 research outputs found

    Method and apparatus for eliminating luminol interference material

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    A method and apparatus for removing porphyrins from a fluid sample which are unrelated to the number of bacteria present in the sample and prior to combining the sample with luminol reagent to produce a light reaction is disclosed. The method involves a pre-incubation of the sample with a dilute concentration of hydrogen peroxide which inactivates the interfering soluble porphyrins. Further, by delaying taking a light measurement for a predetermined time period after combining the hydrogen peroxide-treated water sample with a luminol reagent, the luminescence produced by the reaction of the luminol reagent with ions present in the solution, being short lived, will have died out so that only porphyrins within the bacteria which have been released by rupturing the cells with the sodium hydroxide in the luminol reagent, will be measured. The measurement thus obtained can then be related to the concentration of live and dead bacteria in the fluid sample

    Evaluation program for secondary spacecraft cells: Acceptance tests of Gulton Industries 100.0 ampere-hour nickel-cadmium cells

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    Acceptance tests of 100 ampere-hour nickel-cadmium cells for inclusion in life cycle program of secondary spacecraft cell

    Evaluation program for secondary spacecraft cells: Evaluation of storage methods, open circuit versus continuous trickle charge, Sonotone 3.5 ampere-hour sealed nickel-cadmium secondary spacecraft cells

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    Twenty-five cells were used in a five-year test to compare, after each successive one-year storage period, the discharge and charge characteristics of charged cells on open circuit versus that of cells on continuous trickle charge. The test procedure, instrumentation, and results are described. Based on the test results, the following recommendations were made: (1) If the user's purpose will allow a rejuvenation cycle or two after a long storage period, the open circuit regime will likely give slightly greater capacity. (2) If the user's purpose demands immediately available power following a long storage period, the trickle charge method of storage is definitely the regime to use

    Evaluation program for secondary spacecraft cells - Acceptance test of General Electric Company 6.0 ampere hour nickel cadmium cells /ceramic seals with nickel braze/

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    Acceptance tests including capacity, cell short, high vacuum leak, overcharge, and internal resistance of nickel-cadmium secondary cells with nickel braze ceramic seals for spacecraf

    Accelerated battery-life testing - A concept

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    Test program, employing empirical, statistical and physical methods, determines service life and failure probabilities of electrochemical cells and batteries, and is applicable to testing mechanical, electrical, and chemical devices. Data obtained aids long-term performance prediction of battery or cell

    Loss of Larval Fish by Epilimnial Discharge From DeGray Lake, Arkansas

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    Weekly samples of larval fish were collected from water discharged from the epilimnion of DeGray Lake into the tailwaters, for power generation, from April through August, 1976 and 1977. Peak rates of loss measured were 1.4 larvae/m³ in May, 1976 and 2.7/m³ in April, 1977. Sunfish, shad and crappie made up 97% of an estimated 83.3 million fish lost in 1976, and 98% of 122.4 million lost in 1977. The most critical period for larval fish loss extended from the last week of April to the first week of June. No definite relationships were noted between length of the power generation period or power generation rate, and rate of larval fish discharge. Diel collections showed the rate of larval fish discharge to be lower and more uniform during darkness than during daylight

    An Accounting of the Sources of Steller Sea Lion, Eumetopias jubatus, Mortality

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    During 1991–2000, the west-are additional mortalities that fueled the ern stock of Steller sea lions, Eumetopias decline. We tabulated the levels of reported jubatus, declined at 5.03% (SE = 0.25%) anthropogenic sources of mortality (sub- per year, statistically significant rates (P 8.2% partition the various sources of “additional” per year). Using a published correction mortalities as anthropogenic and as addifactor, we estimated the total non-pup pop-tional mortality including some predation. ulation size in Alaska of the western stock We classified 436 anthropogenic mortalities of Steller sea lions to be about 33,000 ani-and 769 anthropogenic plus some predation mals. Based on a published life table and mortalities as “mortality above replace-the current rate of decline, we estimate that ment”; this accounted for 26% and 46% of the total number of mortalities of non-pup the estimated total level of “mortality above Steller sea lions during 1991–2000 was replacement”, respectively. The remaining about 6,383 animals; of those, 4,718 (74%) mortality (74% and 54%, respectively) was are mortalities that would have occurred if not attributed to a specific cause and may be the population were stable, and 1,666 (26%) the result of nutritional stress

    Fishes of the Caddo River, Arkansas, After Impoundment of DeGray Lake

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    Fifty-five collections of fishes were made with small-mesh seines and electrofishing gear in the Caddo River and four of its tributaries during 1974-75. Eighty-two species representing 17 families were collected; 14 of the species had not previously been reported from the Caddo River
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